The changes that occur as the result of a psychotherapeutic process may be divided according to whether they are (1) intended or (2) unintended. The vast literature dealing with the process of psychotherapy has assumed, with very few exceptions, that the changes in the patient that take place during treatment are secondary to the direct, intended efforts of the therapist. These assumptions have not been proved, and those reports that are available concerning the relative efficacy of various types of therapy1-3 allege that all therapies produce very similar results suggesting that there must be very potent, effective unintended features common to all types of psychotherapy. While the relative impact of the intended and unintended aspects have not been studied sufficiently, many of the factors pertaining to the unintended effects may be outlined.
Many unintended factors correspond to those factors which pertain
LESSE S. Placebo Reactions and Spontaneous Rhythms in Psychotherapy. Arch Gen Psychiatry. 1964;10(5):497-505. doi:10.1001/archpsyc.1964.01720230059006